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|
package dynamodb
import (
"encoding/json"
"errors"
"fmt"
"reflect"
simplejson "github.com/bitly/go-simplejson"
)
type Stream struct {
Server *Server
Arn string
}
type StreamListItemT struct {
StreamArn string
StreamLabel string
TableName string
}
type SequenceNumberRangeT struct {
EndingSequenceNumber string
StartingSequenceNumber string
}
type ShardT struct {
ParentShardId string
SequenceNumberRange SequenceNumberRangeT
ShardId string
}
type StreamDescriptionT struct {
CreationDateTime float64
KeySchema []KeySchemaT
LastEvaluatedShardId string
Shards []ShardT
StreamArn string
StreamLabel string
StreamStatus string
StreamViewType string
TableName string
}
type RecordT struct {
AwsRegion string
EventID string
EventName string
EventSource string
EventVersion string
StreamRecord *StreamRecordT
}
type StreamRecordT struct {
Keys map[string]*Attribute
NewImage map[string]*Attribute
OldImage map[string]*Attribute
SequenceNumber string
StreamViewType string
SizeBytes int64
}
type listStreamsResponse struct {
Streams []StreamListItemT
}
type describeStreamResponse struct {
StreamDescription StreamDescriptionT
}
var ErrNoRecords = errors.New("No records")
func (s *Server) ListStreams(startArn string) ([]StreamListItemT, error) {
return s.LimitedListTableStreams("", startArn, 0)
}
func (s *Server) LimitedListStreams(startArn string, limit int64) ([]StreamListItemT, error) {
return s.LimitedListTableStreams("", startArn, limit)
}
func (s *Server) ListTableStreams(table, startArn string) ([]StreamListItemT, error) {
return s.LimitedListTableStreams(table, startArn, 0)
}
func (s *Server) LimitedListTableStreams(table, startArn string, limit int64) ([]StreamListItemT, error) {
query := NewEmptyQuery()
if len(table) != 0 {
query.addTableByName(table)
}
if len(startArn) != 0 {
query.AddExclusiveStartStreamArn(startArn)
}
if limit > 0 {
query.AddLimit(limit)
}
jsonResponse, err := s.queryServer(streamsTarget("ListStreams"), query)
if err != nil {
return nil, err
}
var r listStreamsResponse
err = json.Unmarshal(jsonResponse, &r)
if err != nil {
return nil, err
}
return r.Streams, nil
}
func (s *Server) DescribeStream(arn, startShardId string) (*StreamDescriptionT, error) {
return s.LimitedDescribeStream(arn, startShardId, 0)
}
func (s *Server) LimitedDescribeStream(arn, startShardId string, limit int64) (*StreamDescriptionT, error) {
query := NewEmptyQuery()
query.AddStreamArn(arn)
if len(startShardId) != 0 {
query.AddExclusiveStartShardId(startShardId)
}
if limit > 0 {
query.AddLimit(limit)
}
jsonResponse, err := s.queryServer(streamsTarget("DescribeStream"), query)
if err != nil {
return nil, err
}
var r describeStreamResponse
err = json.Unmarshal(jsonResponse, &r)
if err != nil {
return nil, err
}
return &r.StreamDescription, nil
}
func (s *Server) NewStream(streamArn string) *Stream {
return &Stream{s, streamArn}
}
func (s *Stream) DescribeStream(startShardId string) (*StreamDescriptionT, error) {
return s.Server.DescribeStream(s.Arn, startShardId)
}
func (s *Stream) LimitedDescribeStream(startShardId string, limit int64) (*StreamDescriptionT, error) {
return s.Server.LimitedDescribeStream(s.Arn, startShardId, limit)
}
func (s *Server) GetShardIterator(streamArn, shardId, shardIteratorType, sequenceNumber string) (string, error) {
query := NewEmptyQuery()
query.AddStreamArn(streamArn)
query.AddShardId(shardId)
query.AddShardIteratorType(shardIteratorType)
if len(sequenceNumber) != 0 {
query.AddSequenceNumber(sequenceNumber)
}
jsonResponse, err := s.queryServer(streamsTarget("GetShardIterator"), query)
if err != nil {
return "unknown", err
}
json, err := simplejson.NewJson(jsonResponse)
if err != nil {
return "unknown", err
}
return json.Get("ShardIterator").MustString(), nil
}
func (s *Stream) GetShardIterator(shardId, shardIteratorType, sequenceNumber string) (string, error) {
return s.Server.GetShardIterator(s.Arn, shardId, shardIteratorType, sequenceNumber)
}
func (s *Server) GetRecords(shardIterator string) (string, []*RecordT, error) {
return s.LimitedGetRecords(shardIterator, 0)
}
func (s *Server) LimitedGetRecords(shardIterator string, limit int64) (string, []*RecordT, error) {
query := NewEmptyQuery()
query.AddShardIterator(shardIterator)
if limit > 0 {
query.AddLimit(limit)
}
jsonResponse, err := s.queryServer(streamsTarget("GetRecords"), query)
if err != nil {
return "", nil, err
}
jsonParsed, err := simplejson.NewJson(jsonResponse)
if err != nil {
return "", nil, err
}
nextShardIt := ""
nextShardItJson, ok := jsonParsed.CheckGet("NextShardIterator")
if ok {
nextShardIt, err = nextShardItJson.String()
if err != nil {
message := fmt.Sprintf("Unexpected response %s", jsonResponse)
return "", nil, errors.New(message)
}
}
recordsJson, ok := jsonParsed.CheckGet("Records")
if !ok {
return nextShardIt, nil, ErrNoRecords
}
recordsArray, err := recordsJson.Array()
if err != nil {
message := fmt.Sprintf("Unexpected response %s", jsonResponse)
return nextShardIt, nil, errors.New(message)
}
var records []*RecordT
for _, record := range recordsArray {
if recordMap, ok := record.(map[string]interface{}); ok {
r := parseRecord(recordMap)
records = append(records, r)
}
}
return nextShardIt, records, nil
}
func (s *Stream) GetRecords(shardIterator string) (string, []*RecordT, error) {
return s.Server.GetRecords(shardIterator)
}
func (s *Stream) LimitedGetRecords(shardIterator string, limit int64) (string, []*RecordT, error) {
return s.Server.LimitedGetRecords(shardIterator, limit)
}
func parseRecord(r map[string]interface{}) *RecordT {
record := RecordT{}
rValue := reflect.ValueOf(&record)
keys := []string{"awsRegion", "eventID", "eventName", "eventSource", "eventVersion"}
for i, key := range keys {
if value, ok := r[key]; ok {
if valueStr, ok := value.(string); ok {
rValue.Elem().Field(i).SetString(valueStr)
}
}
}
if streamRecord, ok := r["dynamodb"]; ok {
if streamRecordMap, ok := streamRecord.(map[string]interface{}); ok {
record.StreamRecord = parseStreamRecord(streamRecordMap)
}
}
return &record
}
func parseStreamRecord(s map[string]interface{}) *StreamRecordT {
sr := StreamRecordT{}
rValue := reflect.ValueOf(&sr)
attrKeys := []string{"Keys", "NewImage", "OldImage"}
numAttrKeys := len(attrKeys)
for i, key := range attrKeys {
if value, ok := s[key]; ok {
if valueMap, ok := value.(map[string]interface{}); ok {
attrs := parseAttributes(valueMap)
rValue.Elem().Field(i).Set(reflect.ValueOf(attrs))
}
}
}
strKeys := []string{"SequenceNumber", "StreamViewType"}
numStrKeys := len(strKeys)
for i, key := range strKeys {
if value, ok := s[key]; ok {
if valueStr, ok := value.(string); ok {
rValue.Elem().Field(i + numAttrKeys).SetString(valueStr)
}
}
}
intKeys := []string{"SizeBytes"}
for i, key := range intKeys {
if value, ok := s[key]; ok {
if valueNumber, ok := value.(json.Number); ok {
if valueInt, err := valueNumber.Int64(); err == nil {
rValue.Elem().Field(i + numAttrKeys + numStrKeys).SetInt(valueInt)
}
}
}
}
return &sr
}
|
